Ten descended on the air base, three on the naval base. The Russians say seven were shot down by anti-aircraft missile defences, and six were hacked into and captured intact.

Each of them carried several explosive devices under their wings, and were guided from up to 100km away by GPS.

A number of drones were captured before they could drop their payloads.
Photo credit: Russian Ministry of Defence.

Bombs attached the wings of one drone.
Photo credit: Russian Ministry of Defence

"Russian specialists are determining supply channels through which terrorists had received the technologies and devices, as well as examining type and origin of explosive compounds used in the IEDs," the ministry said.

Russia has accused Turkish-backed rebel forces of launching the drones from Idlib, in Syria's northwest. Russia is allied with Syrian President Bashir al-Assad, whose forces have been fighting Western-backed rebels and Islamic militants for nearly a decade.

The ministry said the "engineering decisions... could be received from [countries] with high-technological capabilities of satellite navigation and remote dropping control of professionally assembled improvised explosive devices in assigned coordinates... Until recently, terrorists did not have all this."